Field of the Disclosure
This disclosure generally relates to a heat exchanger unit with characteristics of improved: airflow, noise reduction, cooling efficiency, and/or structural integrity. Other aspects relate to a system for monitoring airflow through a heat exchanger unit, or fouling related thereto. In particular embodiments, a monitoring module is mounted externally to the heat exchanger unit of a monitored system, the system being usable to monitor fouling of the unit, and provide an associated warning. The monitoring module may be operably associated with a durable, rugged airflow sensor assembly.
Background of the Disclosure
Whether its refrigeration, hot showers, air conditioning, and so on, the function of heating and cooling is prevalent in today's residential and industrial settings. One area of relevance is the oil and gas industry, including exploration, upstream, and downstream operations where the ability to heat and/or cool is critical. Upstream operations can include drilling, completion, and production, whereas downstream operations can include refining and other related hydrocarbon processing, all of which utilize a vast amount of process equipment including that which provide heat transfer. To be sure, the background of the disclosure is relevant elsewhere, but for brevity discussion is focused on O&G.
Common settings are nothing short of challenging in the sense that in many instances operations and processes (and related equipment) are exposed to environmental conditions, such as extreme heat, cold, wind, and dust (including natural amounts of particulate, as well as that caused by the operation of equipment and vehicles).
It is routine to have (indeed, need) some type of heat exchange ability in such settings. As set forth in U.S. Ser. No. 15/477,097, an example operation in an industrial setting may include one or more frac pump units. Each unit is typically operable with a pump and engine mounted or otherwise disposed thereon, as well as a radiator (or analogously referred to as cooler, heat exchanger, etc.). As mentioned before, equipment like this must be rugged and durable in order to have long-term operational capacity and effectiveness.
The radiator is configured for cooling one or more hot service fluids associated with the equipment of the frac pump unit, such as lube oil or jacket water. The radiator typically includes a ‘core’ of stacked fins, with one part of the core providing a flow are for the service fluid(s), while another part of the core provides a proximate, albeit separate, flow area for ambient air. A fan is used to blow or pull air through the stacked fins, the air being a low or moderate enough temperature to cool the service fluid, which is then recirculated in a loop.
The stacked fins often have a configuration that is tantamount to an extensive amount of small air passageways proximate to (albeit separate from) service fluid passageways, whereby the air and the service fluid can ‘exchange heat’ via the surface material of the stacked fins between the passageways (e.g., aluminum).
Over time airborne dirt in and other particulate in the air will begin to deposit on the air intake side (and elsewhere), resulting in a fouled radiator. Fouling can seriously deteriorate the capacity of the surface of the fins to transfer heat under the conditions for which they were designed. Among other problems, the fouling layer has a low thermal conductivity which increases the resistance to heat transfer and reduces the effectiveness of heat exchangers. In addition, fouling reduces the cross-sectional area in the passageways, which causes an increase in pressure drop across a heat exchanger.
Radiator fouling affects both capital and operating costs of heat exchangers (and overall processes). Higher capital expenditures include that for excess surface area (for heat transfer), extra space, and transport and installation costs. Operating expenditures include that for energy losses due to the decrease in thermal efficiency, increases in the pressure drop through process equipment, and production losses during planned and unplanned plant shutdowns for fouling cleaning.
Moreover, government emissions regulations are forcing engine manufacturers and their customers to reduce emissions from reciprocating engines. Current solutions involve returning the exhaust through heat exchange, which elevates combustion temperature and puts significantly more heat into the cooling system. Tier 4 Final (US and CA) Emission regulations come into effect in 2017 & 2020 will force end users into significant equipment redesign industry wide. See, e.g., http://www.assocpower.com/eqdata/tech/US-EPA-Tier-Chart_2004-2017.php, for general reference.
In summary, fouling of heat transfer surfaces is one of the most important problems in heat transfer equipment. Some have described fouling as the major unresolved problem in heat transfer. Equipment operators world-wide are also trying to reduce maintenance costs. One of the highest maintenance costs any piece of equipment has is cooling system maintenance.
And yet despite these detriments, consideration of improved remediation or management techniques have been largely ignored and unchanged. Conventional techniques include mitigation (such as upstream filtering) and chemical treatment.
Mechanical cleaning is also used, but only during predetermined periodic intervals, namely during a planned shutdown or when an exchanger reaches a point of failure and is no longer operable. This approach relies on extensive cost and resource being allocated toward the antiquated philosophy of operational redundancy.
There is a need in the art to overcome deficiencies and defects identified herein. There is a need in the art to reliably monitor fouling of a radiator. There is a need in the art to provide a real-time warning indication about fouling conditions of a radiator.
There is a need in the art for a monitoring system that is durable for use in outdoor and other difficult environmental conditions. There is a need in the art for a monitoring system capable of high degree of sensing accuracy, yet impervious to or otherwise able to withstand external conditions. There is a further need for an improved rugged sensor assembly suitable for ongoing and extended use in association with the monitoring system in extreme environmental conditions.
There is a need in the art for a method of doing business that includes monitoring and servicing of radiators, especially when the radiator reaches various stages of fouling or provides other indication requiring attention. There is a need in the art to clean a fouled radiator with little or no downtime.
There is a need in the art for a monitoring module that can be retrofitted to any existing heat exchanger, including of great importance to a heat exchanger that has one or more sides (or surfaces) exposed to ambient air.
There is a particular need in the art for a monitoring system that is readily adaptable and compatible to radiators associated with different pieces of heat generating equipment, such as an engine, a motor, a pump, or a genset useable in a wide range of settings.